1. Field of the Invention
This invention relates to agricultural tillage equipment and, in particular, this invention relates to a tine and tine system for aerating soils with minimal disruption of the soil profile.
2. Background of Plows Invention
Persons producing crops are often confronted with two issues: soil compaction and soil erosion. Solutions to these issues are often contradictory in nature. Soil compaction occurs due to such phenomena as rainfall, overhead irrigation, tillage implements (e.g., tractors, planters, cultivators), and livestock. Soil compaction causes problems such as reduced water infiltration, restricted crop root growth, and lower amounts of oxygen for general plant growth and development. Tillage methods, such as moldboard plowing, were traditionally used to eliminate and/or reduce soil compaction. However, moldboard plows typically left the soil surface bare and exposed to wind and water erosion. To reduce soil erosion, compaction was often eliminated by using other tillage implements with sweeps or chisel-points. These implements had the advantage of leaving surface crop residue more-or-less intact to reduce soil loss due to erosion. However, the root structure of the crop plant residue was totally disrupted when these implements were used. Moreover, tillage practices with these implements often adversely affected trafficability and resulted in increased soil bulk density.
Without intending to limit the present invention, it is believed that silt soil particles are only slightly heavier than water. As water moves downward in a soil profile, the water transports silt particles with it, e.g., within the A-horizon. As the downward movement of water slows, the silt particles are deposited within the A-horizon to form a nearly indistinguishable layer initially. As this process continues over time, e.g., with additional precipitation, this layer becomes discrete and identifiable. Mechanical analysis of soil profiles verifies that silt accumulates over time at different depths, in differing soil types, with differing organic matter content, and root system environments. The creation and existence of this “density layer” (or accumulated silt) is one condition requiring tillage operations. Perforation of this silt layer and fracturing of the same restores more rapid water intake of soils. It is not necessary to lift, turn, and/or redistribute the silt in the A-horizon to restore water movement. Aeration of soil is, in fact, a true tillage since one of the major functions of tillage is to restore the water intake capability of a given soil. The accumulation of silt serves as a barrier to the exchange of water and soil atmosphere within a given soil. The importance of this phenomenon in causing sheet erosion in no-till situations and gully erosion in cases of traditional primary tillage techniques is directly related to the importance of the present invention.
In addition to the concerns stated above, moldboard plows and chisels are unsatisfactory in aerating soil profiles in which stands of perennials (e.g., pasture grasses, alfalfa) have been established. Obviously, using moldboard plows or chisels would destroy the stand of perennials, as well as potentially expose the surface of the soil to wind and water erosion. However, soil compaction frequently occurs in soils with perennial crop stands due to the effects of rain, irrigation, livestock traffic, tractors and baling equipment, and the like.
U.S. Pat. No. 4,383,580, issued 17 May 1983 to Huxford and hereby incorporated by reference, discloses an agricultural implement asserted as being suitable for aerating soils and pastures. The agricultural implement includes a frame attachable to a three-point tractor linkage, a plurality of shafts rotatably mounted on the frame, and a plurality of cutting blades projecting from each of the rollers. The blades are formed from plate material and are preferably formed to a point. Various edges of the blade are preferably doubled to assist the implement in cutting the soil without undue lifting or tearing of the soil surface.
U.S. Pat. No. 4,619,329, issued 28 Oct. 1986 to Gorbett and hereby incorporated by reference, discloses a soil aerator with a frame. A rotatable drum is mounted on the frame. The enclosed opposing ends of the drum carry axles, which are mounted within the frame, whereby the drum is rotatable with respect to the frame about the longitudinal axis of the drum. A plurality of triangular-shaped teeth are arranged in rows on an outer cylindrical surface of the drum. Each of the rows of teeth forms a chevron-shaped pattern with respect to the next succeeding row of teeth.
U.S. Pat. No. 4,840,232, issued 28 Jun. 1989 to Mayer and hereby incorporated by reference, discloses soil aerating equipment having a frame and at least one pair of shafts. The shafts are freely and rotatably mounted on the frame for rotation about the shaft longitudinal axes. The shafts extend in rearwardly inclined, opposite directions from a centerline of the frame. The rearward inclination of the shafts is adjustable to desired angles in the range of from about 90 degrees to about 120 degrees to the direction of travel. Each shaft carries a series of soil-engaging, substantially planar tines extending therefrom in vertical planes and positioned to sequentially engage and penetrate the soil with consequent rotation of the shafts when the frame is moved in the direction of travel. Each tine has a central, longitudinal axis, which extends behind the shaft rotational axis at a distance therefrom in the range of about 0.25 to about 1.75 inch. Each tine is twisted about a tine central, longitudinal axis at a fixed angle to a vertical plane parallel to the direction of travel in the range of from about 1 degree to about 30 degrees.
U.S. Pat. No. 5,020,602, issued 4 Jun. 1991 to Dellinger and hereby incorporated by reference, discloses an aerator for lawns and the like. The aerator has spiders formed from four identically-formed members. Each of these members has a tine on each end. Therefore, four members provide eight tines for the spider. The members are relatively narrow. Filler members at each end of the tine members provide stability to the spider. The spiders are carried by a frame. The frame carries a weight-receiving tray for carrying weight to assure penetration of the tines. Springs carry the tray on the frame, so that the springs will absorb energy resulting from engaging an impenetratable object.
U.S. Pat. No. 5,460,229, issued 24 Oct. 1995 to Mattis and hereby incorporated by reference, discloses a field aerator apparatus asserted as being useful for aerating grass or hay ground. The apparatus includes elongated spikes on a cylindrical drum. As the apparatus is towed across a field, the spikes penetrate and loosen the soil, as well as provide openings in the soil to improve water penetration and reduce water run-off. The spikes are secured to bands encircling the drum. The spacing between bands is adjustable, so that the spacing between spikes can be adjusted.
U.S. Pat. No. 5,611,291, issued 18 Mar. 1997 to Pogue and hereby incorporated by reference, discloses an aerator and seeder for untilled pasture land. The implement includes a frame and a cylindrical drum. The drum is rotatably mounted on the frame by a co-rotatable axial shaft. A plurality of rigid prongs are provided on the cylindrical surface of the drum. The prongs penetrate, agitate, and aerate the soil as the drum is rolled over the land to be seeded.
Many of the above-referenced documents are directed to reducing exposure of a soil to the erosion and enhancing trafficability thereon. The implements described use tines performing vertically to penetrate the soil profile, thereby reducing or eliminating soil compaction and aerating or restoring normal air-water exchange in the soil profile as well. These implements further minimize exposure to erosion by retaining above-ground and below-ground crop residue. However none of the implements described in these documents 1) provides tines without abrupt radius changes; 2) provide a tine with a cavity (and optional soil retaining surfaces thereon) to catch soil and thereby abrade soil on the surface of the tine against soil being aerated; 3) provide a tine assembly with a key slot on both sides of the tine base to enable the tine to be reversibly mounted; and 4) provide a tine with a slot or opening for injecting fluids (e.g., fertilizer) into the soil during an aeration procedure.